How do I stop before the full price starts?

Cancel it in your iPhone Settings:

1. Open the Settings app.
2. Tap your name at the top.
3. Tap Subscriptions, then Veilleuse.
4. Tap Cancel Subscription.

Do it at least 24 hours before the end of the first month. You keep the Family plan until the end of that month. Then the family goes back to the Free plan. Nothing is deleted.